Move glue code of blob channel to blimp_client_context_impl.

blimp/net/blob_channel/helium_blob_receiver_delegate.h

Index: blimp/net/blob_channel/helium_blob_receiver_delegate.h
diff --git a/blimp/net/blob_channel/helium_blob_receiver_delegate.h b/blimp/net/blob_channel/helium_blob_receiver_delegate.h
index f2f817d94f9aa66a7576aa21b63acb37459e23a5..5fd1eb8a901e047749c5a4bef862b995259896d6 100644
--- a/blimp/net/blob_channel/helium_blob_receiver_delegate.h
+++ b/blimp/net/blob_channel/helium_blob_receiver_delegate.h
@@ -28,11 +28,11 @@ class BLIMP_NET_EXPORT HeliumBlobReceiverDelegate
   // Sets the Receiver object which will take incoming blobs.
   void SetReceiver(BlobChannelReceiver* receiver) override;
 
- private:
   // BlimpMessageProcessor implementation.
   void ProcessMessage(std::unique_ptr<BlimpMessage> message,
                       const net::CompletionCallback& callback) override;
 
+ private:
   BlobChannelReceiver* receiver_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(HeliumBlobReceiverDelegate);